The ball is put down by a player behind his own goal line when the ball has been put across the goal line by an opponent. Can happen for instance in kick offs, when the kick lands in the end zone and the player returning the kick has no chance to exit the end zone. Does not count as a safety. Takalaiton (Pinomaa)

the act of downing the ball behind one's own goal line after the ball had been propelled over the goal by the opposing team. After a touchback, the team that downed it gets the ball at their own 20-yard line.

when a player who gains possession of a ball in his own end zone kneels to the ground and automatically starts the next play at his own 20-yard line; also awarded if his opponent kicks the ball across the end line.

If the ball falls into a team's end zone and bounces without being caught, a member of that team touches the end zone with the ball without first being outside the end zone, or an intercepting player is tackled before being outside his end zone, it is said to be a touchback and that team starts from its own 20 yard line. In college football, if a pylon (the short red sticks at the corners of the end zone) is touched with the football, that end zone's team gets a touchback.

A condition where a ball is ruled to be dead in an end zone. If a kickoff or punt travels into the end zone untouched, the result is a touchback, and the receiving team gets possession of the ball at it's own 20 yard line.

A play that results in the ball being placed on the 20-yard line. Usually a result of the punter kicking the ball into the end zone, but can also occur if a fumbled ball is knocked out of the end zone by the defense.